Simultaneous Bilateral Traumatic Tibial Post Fracture in Tot
A 60-year-old man with a background of Type 2 diabetes, ischemic heart disease, and obesity (BMI 35) underwent a left TKA in 2008 and then a right TKA 12 months later with the same prosthesis. Both surgeries were carried out by the senior author, using a standard technique with identical implant sizes, and no patellar resurfacing. His recovery from the surgeries was uneventful and he had well-functioning knee replacements for 9 and 10 years although he did report bilateral persistent anterior knee pain for a few years prior to his current presentation.

In 2018 the patient, now 70 years old, fell approximately 3 m from a ladder landing onto the anterior aspect of both knees. Initially, he recovered quickly from soft tissue bruising and knee swelling, but over the next few months developed symptoms especially on his right knee. He is very stoical and only represented 18 months after the fall, complaining of worsened bilateral anterior knee pain and intermittent sharp catching as well as swelling and locking in the right knee. He reported feeling a “lump” on the lateral aspect of his right knee intermittently. Examination of both knees revealed an effusion in the right knee, a symmetric range of motion from 5 to 100°, and there was no obvious prosthetic instability in either tibiofemoral or patella-femoral joints.

Radiographs showed well-aligned prostheses with no signs of loosening, but some patellar wear especially the lateral facets. MRI scans showed, in both knees, erosion of the lateral facets of the patellae, and in the right knee showed what appeared to be a loose body, and the senior author considered the possibility of a broken-off bone cement fragment. The patient was offered bilateral patellar resurfacing in view of the anterior knee pain preceded by arthroscopy of the right knee to ensure localization and removal of the loose body, which can be difficult with open surgery if the loose body has moved to the posterior recesses of the knee. However, with review the evening before surgery, a similar loose body was partly visualized at the edge of an image in the left knee. On the morning of surgery, the patient was advised to have an arthroscopy also of the left knee. Once again, it was assumed that the loose body might be a cement fragment, but it was thought odd to have these in both knees.

During the arthroscopies in January 2020, the true diagnosis was made. It was confirmed that in both knees there was a fracture of the polyethylene post close to the tip. The fractured post tips were found in the lateral gutter in the right knee and the suprapatellar pouch in the left knee and removed. In the left knee, the “loose” body was embedded in synovial tissue which accounted for the lack of swelling, locking, and sharp pain. Open resurfacing of both patellae was undertaken. This allowed thorough examination of the prostheses. The original components were well fixed in both knees, and despite the post fractures with consequent loss of their height, the knees were stable on stress testing in both AP and ML directions, and it was not possible to distract the joints sufficiently to allow the femoral components to “jump” over the remaining polyethylene posts. The rest of the polyethylene was healthy. Prior to surgery direct contact with the TKA manufacturer was made and the senior author was told that since the Journey I prosthesis has been superseded by Journey II TKA, no polyethylene components were available for exchange in Journey I TKAs.

The operative findings were fortunate as any need to revise the polyethylene components would have entailed a complete revision of all components, and thankfully, a decision could be reasonably made to retain the original polyethylene components. The patient has been warned of the risk of future episodes of instability. The patient recovered well from surgery and was discharged home 2 days later. At his 12-month follow-up, the patient reported complete resolution of symptoms.

Source:https://www.karger.com/Article/FullText/516254
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